Glass sheet conveying apparatus



G. F. RITTER, JR

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ATTORNEYS Dec. 23, 1969 Filed Jan. 30, 1967 Dec. 23, 1969 G. F. RITTER, JR

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fl 965ed962m ATTORNEYS United States Patent 3,485,618 GLASS SHEET CONVEYING APPARATUS George F. Ritter, In, Toledo, Ohio, assignor to Libbey- Owens-Ford Glass Company, Toledo, Ohio, a corporation of Ohio Filed Jan. 30, 1967, Ser. No. 612,556 Int. Cl. C031) 13/18 US. Cl. 65273 4 Claims ABSTRACT OF THE DISCLOSURE A conveyor roll having rigid end sections, and a flexible center section which will conform to the surface contour of articles carried by it. The relative lengths of the rigid end sections and flexible center section are such that flat sheets are supported partly on the rigid end sections and partly on the flexible center section; whereas, the same sheets when bent will be supported wholly by the flexible center section.

The present invention relates generally to supporting and conveying apparatus and more particularly to improved rotary apparatus of this character for movably supporting both flat and bent glass sheets while in a heatsoftened condition.

This invention has proven to be of particular utility in handling heat-softened glass sheets within a horizontal type bending apparatus and will be so described herein by way of example.

In the production of curved glass sheets in large quantities, such as is encountered in the commercial production of glazing closures for automobiles or the like, it is customary to convey the sheets successively through a heating area, a bending area and an annealing area, or a chilling area in a substantially continuous manner by means of externally driven roll-type conveyors. During a substantial portion of this bending process, the glass is in a heat-softened state in which it is extremely vulnerable to distortion and surface marring and this vulnerability must be taken into consideration in the design of the conveyor rolls. The problem is particularly acute within the bending area since at different times in the bending cycle the glass sheets must rest upon the same rolls both in a fiat condition and in a bent condition. Unless adequate support can be provided under both conditions, distortion and marring are likely to occur as well as a tendency for the bent glass to relax from its bent condition.

The primary object of the present invention, therefore, is to provide a conveyor roll which offers adequate support to both flat and curved sheets by flexing of a portion of the roll, as required, to conform in shape to the sheets supported upon it.

Other objects and advantages of the invention will become more apparent during the course of the following description when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

FIG. 1 is a side elevation of a typical horizontal press bending apparatus showing a glass sheet to be bent supported on rolls incorporating the present invention;

FIG. 2 is a partial cross-sectional view taken along the line 22 of FIG. 1 depicting the glass sheet in the flat before commencement of the bending operation;

FIG. 3 is a partial cross-sectional view similar to FIG. 2 but depicting the condition of the glass sheet and supporting rolls after completion of the bending operation;

FIG. 4 is a fragmentary longitudinal sectional view of an end portion of one roll illustrating structural details of one embodiment of the invention; and

3,485,618 Patented Dec. 23, 1969 FIG. 5 is an enlarged, fragmentary, longitudinal sectional view of a roll of the invention carrying a glass sheet under condition as illustrated in FIG. 3.

Referring now more particularly to the drawings, the novel features of the present invention have been depicted as incorporated in a type of glass bending apparatus used in press bending; however, it will be apparent that the invention will have utility in any horizontal conveyor application wherein it is desired to accommodate articles that may be either flat or of varying curvature.

A typical press bending apparatus as shown at 10 consists mainly of a rigid framework 11 in which are mounted a substantially stationary upper male mold member 12 and a movable lower female mold member 13, vertically movable Within the rigid framework. The mold members are provided with complemental shaping surfaces, the shaping surface 14 of the upper mold member 12 being generally a continuous surface, while the complemental shaping suface 15 of the lower mold member 13 is of the ring-type which engages only the marginal edge portions of the glass sheet.

The upper mold member 12 is supported from the framework 11 by bolts 16 surrounded by springs 17 which act as cushions to prevent excessive pressure being exerted on the glass by the action of lower mold member 13.

The lower mold member 13 is supported by guide members 18 which allow vertical movement only, said vertical movement being provided by the ram 19 of a pressure-actuated cylinder 20 which bears against the lower mold member.

Flat glass sheets 21 to be bent are transferred into the bending apparatus 10 by conveyor rolls 22 and located in bending position by engagement of their leading edges with stops 23 (one of two shown) each of which is moved by a pressure-actuated cylinder 24 into and out of the sheet path. A photoelectric cell 25 senses the entry of the glass sheets into the bending apparatus, as the sheets interrupt the beam L from light source 26, and initiates the bending cycle by actuating timing mechanisms which control the action of press cylinder 20 to raise and lower the mold member 13 by the ram 19 and in sequence lower and raise the locator stops by the cylinders 24.

When the glass sheet is in position to be bent, it is supported upon conveyor rolls 27. In order to provide clearance for the conveyor rolls 27 and to permit the lower mold member 13 to move vertically into and out of pressing relation with the upper mold member 12, the ring-type shaping element 15 thereof is formed of spaced segments 28 supported on pillars 29 fixed to a base section 30.

Each conveyor roll 27 comprises, in accordance with the invention, rigid end sections or stub shafts 31 and 32 bridged by a resilient intermediate connecting member such as a coil spring 33. The lengths of the rigid end sections and flexible center section are proportioned such that when flat glass sheets are moved into bending position they will rest partly on the rigid sections and partly on the flexible section as illustrated in FIG. 2; whereas, when the glass sheet has been bent it will rest wholly on the flexible section as illustrated in FIGS. 3 and 5. The actual proportions depend upon the size and weight of the glass sheets and the degree of curvature desired.

In mounting the rolls 27, the rigid end stub shafts 31 and 32 are each journaled in individual pairs of spaced bearings 34 to maintain the same in axial alignment; said pairs of bearings being mounted on structural rails 35 along the sides of the bending apparatus 10. The shaft 32 outward of the related bearings 34 is provided with sprocket 36 driven by a chain belt 37, or it may be driven in any other desired manner.

The coil spring 33 is fastened to the stub shafts 31 and 32 by fitting the opposite ends thereof over portions 38 of reduced diameter at the inner ends of said stub shafts. The reduced diameter of the end portions 38 is slightly larger than the inside diameter of the spring 33 to provide a pressed fit with the shaft end portions 38. Since each of the stub shafts is freely rotatable in its respecive bearings 34, this pressed-fit connection of the spring at each of its ends enables the stub shaft 32 with the sprocket 36 to rotatively drive the spring and thereby the oppositely disposed stub shaft 31.

The outside diameter of the spring 33 is substantially the same as the diameter of the main portions of the stub shafts 31 and 32, and, by providing the roll assembly with a covering of a soft, non-abrasive, resilient material such as a tubular sleeve 39 a substantially continuous roll surface will be provided. The sleeve may be of asbestos or fibre glass cloth and secured by stretching it over the roll assembly and fastening the ends with pressure-sensitive tape 40 or by some other suitable means.

In operation, heat softened sheets of glass 21 are transferred from a heating area by conveyor rolls 22 into the bending apparatus 10 where they come to rest against the stops 23, as previously described. At thi point, the glass sheets are substantially flat, as illustrated in FIG. 2, and are supported by both the stub shafts 31 and 32 and the center flexible spring section 33 of the rolls 27. Being so supported, there is little tendency for the central portion of the glass sheets to sag. As the lower mold member 13 lifts the glass sheets from the rolls 27 into I pressing engagement with upper mold member 12, the stops 23 are lowered to a point below the level of the top surfaces of the rolls 27. Upon completion of the bending operation, the glass sheets are returned to the rolls in the bent condition illustrated in FIGS. 3 and 5, wherein the entire weight of the glass is supported by the center spring section 33 causing said section to flex and form a cradle which conforms to the curvature of the bent sheets. As each sheet is returned to the rolls it is immediately transferred, by the rolls, out of the bending apparatus into either an annealing or a tempering zone, whereupon the stops 23 are again raised in readiness to be engaged by another sheet as it enters the bending apparatus.

I claim:

1. In apparatus for the horizontal bending of glass sheets, the combination with an upper mold member, a

lower mold member of substantially ring-type spaced therefrom, said mold members having complemental shaping surfaces, means for moving a heat softened glass sheet into bending position between said spaced mold members, and means for moving said lower mold member upwardly to lift .said sheet and to bend the same against said upper mold member and then downwardly to return the bent sheet to said initial bending position, the improvement consisting of a plurality of rotatable conveyor rolls associated with said lower mold member and positioned to support said heat softened glass sheet in said bending position and to receive the bent sheet from said lower mold member, each of said rolls comprising a pair of stub shafts disposed in aligned spaced end-to-end relation, a flexible connecting member bridging the space between said stub shafts and secured thereto, and a protective, resilient covering for'said flexible connecting member extending over the inner end portions of said stub shafts.

2. The apparatus as defined in claim 1, in which the center section of the roll comprises a coil spring.

3. The apparatus as defined in claim 2, in which the rigid end sections have portions of reduced diameter at the inner ends thereof and said coil spring is fastened to said rigid end sections by a pressed fit.

-4. The apparatus as defined in claim 1, in which the covering consists of a tubular sleeve of glass cloth.

References Cited UNITED STATES PATENTS 644,039 2/1900 Benton 29-126 1,592,444 7/1926 Crowley 65-197 1,863,738 6/1932 Adams 29-126 2,251,714 8/1941 Onions 29-126 2,348,887 5/1944 Drake 65-273 2,960,749 11/1960 Robertson et a1. 29-127 XR 2,960,753 11/1960 Robertson 29-127 XR 3,265,484 8/1966 Ritter 65-275 XR 3,361,552 1/1968 Ritter 65-273 XR 3,421,875 1/1969 Kirkman 65-273 S. LEON BASHORE, Primary Examiner JOHN H. HARMAN, Assistant Examiner US. Cl. X.R. 

